A musical instrument string is made of a core of material and optionally strands of the same or other material spiral-wrapped around the core. The composition and dimensions of the core and the optional wrap are chosen so as to produce the desired tones when the string is caused to vibrate. Common materials for core wires include steel, brass, and nylon. Wrap wires are typically metal, including bronze, brass, tin, aluminum, silver, chrome, steel, and alloys thereof, the choice depending on the sound desired and other characteristics. Different types of musical strings are employed on each kind of instruments such as acoustic guitar, electric guitar, bass guitar, violin, cello, bass, banjo, piano, and harp. Most musical strings require human contact along at least a portion of the strings in order to be played, such as in the fingering and plucking of guitar strings.
Musical strings have historically suffered from corrosion issues due to contact with the ambient environment and human hands, as well as the inherent galvanic activity due to the different reduction potentials between the wrap wire and core wire. While straight (non-wound) strings can be easily wiped of dirt, skin oils, and perspiration after use, wound strings tend to become contaminated with contaminants that cannot easily be removed, providing an electrolytic ambient that further promotes galvanic activity and thus corrosion. Corrosion diminishes the bond between the core wire and wrap wire, altering the strings' characteristics and characteristics of the sounds they produce. After a relatively short period of time, a typical wound string will become musically “dead” due to the compromised bond between the core and wrap wires. In addition, oxidation of the wrap wire may cause further contamination issues as well as friction between the windings causing tonal degradation. Strings that lose their tonal qualities must be removed from the instrument and replaced. This process is burdensome, time consuming, and expensive for musicians who play frequently and require high tonal quality.
Over the years various efforts have been made to solve this vexing problem of corrosion due to the ambient environment and human contamination, with various degrees of success. For example, wound strings are often plated with a metal that is more corrosion-resistant than the wrap wire or coated with a polymer that is intended to prohibit contaminants from infiltrating the windings. For example, because PTFE and ePTFE are so slippery, they have been applied to the outside of the wrapped string to protect the strings from contamination sticking to the string. Similarly, polymer coatings have been applied to the core wire in an attempt to protect the strings from contamination and resultant corrosion, but were unsuccessful because the polymer coating prevented a good bond between the core wire and the wrap wire. Core wires of hexagonal cross-section have been used to improve the bond between the core and the wrap wire, but the resultant tone is not as warm as that from round core strings.
A need exists, therefore, to reduce corrosion of musical strings and keep the desired tonal quality. An object of this invention is to provide a method of making strings that reduces corrosion at the core-to-wrap interface. Another object of this invention is to provide a method of making strings that improves the core wire-to-wrap wire bond to prevent contamination from getting to the core wire. Another object of this invention is to provide a method of making strings that reduces corrosion at the core-to-wrap interface caused by inherent galvanic activity between the wrap wire and core wire.